What is red berry mite?

Red berry mite is a microscopic (<0.2mm) whitish mite that sucks sap from flowers and fruit of blackberries, causing uneven ripening. It does not affect other cane fruits.

Symptoms

Red berry mites overwinter under bud scales and become active on the foliage during the spring. When in bloom the mites move onto the flowers and developing fruits.

The first fruits to develop usually ripen fully but later fruits show increasingly patchy ripening, with some parts of the berries remaining hard and red or green. The patchy ripening is sometimes referred to as ‘red-berry’ disease.

Control

There are no suitable pesticides available to home gardeners for control of the mite and so the damage has to be tolerated. Heavily affected canes can be cut to ground level as soon as the problem is noticed and binned (including council compost) or burnt. Consider replacing canes with persistent problems of red berry mite.

Partly ripened berries can be used for cooking, making jam or wine.